Agelong Tree 6 for Windows can import .atd, .at4 and at5 data files. Click “File” - “Import” - “Version 3, 4, 5 file”.

Agelong Tree 6 for macOS and Linux can import .at5 files. Click “File” - “Import” - “Version 5 file”.

When importing data, Agelong Tree creates .atdb file with you data, and it also uses the documents folder when creating portraits, so make sure that documents folder is available together with the .atd, .at4 or .at5 file.